KAA, IOT Ignite, PTC thingworkx, BEZIRK, Bosch IoT suite, Carriots, IoT eclipse.ora, Thingsboard are some of the IoT platform highlighted by the authors. Among them useful for smart city solutions are Bosch, Kaa, Firmware, CISCO, IBM and Cariots. The SNAP4CITY architecture is explained clearly and shows how IoT and smart city works. Simulations are done to check the mobility operator and view the driver to detail how IoT and its sensors work in Smart city applications. AAMA tool is used to monitor the real time data from the IoT sensors in smart city application. The performance are analyzed by monitoring communications bandwidth and number of messages transferred.